Maths: Carroll diagrams

We looked at Carroll diagrams last term in the run-up to our exams. Now we have time to look at them again, more thoroughly. We have to be careful when choosing titles for the rows and columns of Carroll diagrams. Whatever the first column is entitled, the second column must be NOT what the first column is. The same applies to the first row and the second row. The second row must be NOT whatever the first row is. Can you think of a number that could go in the bottom left part of the diagram? It must be less than 50, and it must be a multiple of 10.

The Carroll diagram on the board above is taken from the Abacus book. The two sentences at the bottom of the board are true, based on the information in the diagram. Can you think of other true sentences that fit the information in the diagram?

At home please finish Abacus page 63. Remember to use a full page for question 8, and a full page for question 9. That way you have enough space to draw the shapes inside the Carroll diagram. Did you know that the Carroll diagram was invented by Charles Dodgson, the writer of Alice's Adventures in Wonderland? He used the name Lewis Carroll.